The missing children are 12-year-old Hugo, 6-year-old Merari and 3-year-old Jenh Carlos. San Pablo police initially said their last names were Ortez, but the CHP has since announced in an Amber Alert that the children all have the last name of Anguiano.

Their father, whose name has not yet been released, was found shot to death in San Pablo Monday morning, police said.

Around 7:55 a.m. officers received reports of a man found dead from a gunshot wound in the backyard of a home in the 1600 block of 16th Street, according to San Pablo police.

Officers found the man and pronounced him dead at the scene.

Police said a preliminary investigation indicates that the victim’s three children, who live with him, as well as their mother, who doesn’t live at the home, have not been located.

Police said investigators have not determined a motive for the killing.

Anyone with information about the case is asked to call San Pablo police at (510) 215-3150 or the West Contra Costa Crime Stoppers Tip Line at (510) 799-8255 or 911 if the children are located.